Voltage-regulating system.



PATENTED JULY 28, 1908.

W. MERRILL. VOLTAGE REGULATING SYSTEM.

APPLIGATION FILED OUT. 27, 1906.

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'WILBUB MERRILL, OF SOHENEGTADY, NEW YORKJASSIGNOR TO GENERAL ELECTRICCOMPANY, A GORPORA '1 ION OF NEW YORK.

VQLTAGE-REGULATING SY$WE16L citizen or the United States, residing atSchenectady, county of Schenectady, State of -New York, have inventedcertain new and,

useful Improvements in Voltage-Regulating; Systems, of which thefollowingis a specifi-Z cation.

My invention relates tothe control of clec v 10 trio circuits requiringvariableoltage, and is particularly applicable to the control'oflighting circuits in theaters. Such circuits are ordinarily arrangedwithlarge rheostatsfi in each circuit, so thatthe brilliancyoi the 1*5 lampsof the several circuits may be independently controlled by operatingrheostats.

I Since in theater lighting a large number of the lamps are operated forlong periods at low voltages, not only is a great amount of powerwasted, in the rheostatabnt'a rheostats must be of very largc size tocarry; the current continuously without. over-heating. By substitutingfor the usual rheostat' in each circuit, a counter-electromotive force}generator with means for controlling its field-' strength, and providingmean-s for connect-. 'ing each lamp circuit directly to the source ofcurrent, or indirectly through the counterelectromotive'force generator,the power usuallywasted in rheostats maybe saved. Thus, when the lampsare burning at full hrilliancy they are supplied directly from the maincircuit. ,When a lower voltage is required, the

drop in jvoltage is obtained by counter-sled.

tromo tive force, which, instead of wasting power in heat, returns powerto the source.

Myinyention consists in arranging the switch for cutting each generatorinto and out oi' circuit, so that it is automatically actu 40-.atediwhe'n the field-circuit of the generator is closed; By means ofthis arrangement the main circuit conductors neednolt be hrought to thecontrolling switchesat all, and great economy in wiring is secured.

'My invention further comprises an ar rangement of field rheostats, suchthat each generator may he controlled independently, or a plurality. ofs im u-ltaneously,

Myinventio-n will best be understood by reference to the accompanyingvdrawing, which shows diagrammatically yariable voltage control systemarranged'in accord ance with my invention.

Specification of Letters Patent.

generators may he controlled Patented July as, i908.

Application filed Gctober 2?, 3.906. gerial lie. 340,313.

In the drawing, A and A? are main conductors representing a source ofcurrent;

B to B represent lamp circuits supplied from the mains.

C to Crepresent the armatures of counterelectromotive force generators,the fields be- -ing indicated by c to c".

D represents the driving means for the generators, and may convenientlybe a shunt- .Wound motor supplied from the mains, as shown, carrying onits shaft the armatures of I all the generators.

E to E represent the iield-rhedstats for .zth several generators.

F to F represent electro-magnetically ac- ='tuated switches controlledby the field rheo- --stats, and arranged normall T to connect the-'several lamp-circuits directl to the mains, --but when energized, toconnect the lamp-cirrcuits to the mains indirectly through the ar--matures of the several generators. I E represents a large rheostatadapted to control the'fields of a plurality of generatorssimultaneously.

e to e represent switches arranged to con nect three generatorfieldseither to the indii vidual rheostats or to the large rheostat E.

' The operation of the system is as follows: .Vv'hen full brilliancy isrequired on the lamp the positions shown, so that the magnet- Zoneextending from conductor A through 7 the field 0 and through theresistance of rheosta't E to conductor A and the other extending fromconductor A through the magnet winding of the magnetically actuatedswitch F and through the semi-circular contacts of rheostat E toconductor A The field C is consequently sup lied with its minimum.current and at t e same time B .to the mains through the armature C Theintroduction of the generator-armature .into the lamp circuit is thusproduced automatically upon, the closing of the field-circuit [of thegenerator. -The rheostat-arm may be ically-actu ated switches F to F aredenerswitch F is energized, connecting the circuit.

circuits, the rheostats E .to E and E are in I moved successively overthe several resist electroinotive force generator acts as a motor,

tending to drive the motor D as a generator, so as to return energy tothe mains.

W 1th the switches a", c and e 1n the posi tion shown, each one of thegenerators may becontrolled independently. .It' is desired to controlthe three .rators C, C and C simultaneously, the switches c, c and a maybe shifted to their other positions, in which the three generator fieldsare conected in parallel to the large rheostat E. It will be seen thatthis large rheostat is con ected, to the three 1nagneticallymctuatedswitches F F andf, so that when this rheostat is moved to close thefield-circuits, the three generatoner-matures will sin1ultancously becut into their respective lamp circuits.

hat I claim new and desire to secure by Letters Patent of the UnitedStates, is,. 1. In combination, a source of current, a

vplurality oicircuits normally supplied (ii-- rectly therefrom, aplurality of counter-electromotiv-force generators, adjustableindividual field rheo'stats connected to the fields of each generator,and relays operatively eaesza a conductor of each of the circuitssupplied by the source of current from the source and to connect theseconductors to the source each through the armature of a separategenerator, p

2. In combination, a source of current, a plurality of circui tsnormally supplied directly therefrom, a plurality of counter-electrornotive-force generators, adjustable individual field rheostatsconnected to the fields of each generator, relays o cratively connectedto the individual d rheostats having, their contacts arranged todisconnect a conductor of each or circuits supplied-by the source oicurrent tron: the source and to connect conductors to the source eachthrough the armature of a separate generator, and an adjustablefield-rheostat adjustablyconncctcd to a plurality of generator fields inparallel operatively connected to a lity of relays for simultaneouslyoperati the relaysand simultaneously controlling thev voltage of thegenerators connected to the'circuits by the relays.

In witness whereof, I have hereunto set'rny hand this 25th day ofOctober, 1-906.

WILBUR ll. MERRILL.

Witnesses:

ALEX. F. MAcDoNALn, HELEN ORFORD.

